Bacterial spoilage of bleached-flax rove treated with sub-lethal concentration of biocides

Summary Bacterial species capable of causing spoilage of biocide-treated and untreated-bleached flax roves were present in gutters, troughs and splash boards of spinning frames and also in the atmosphere around these frames. The common bacterial isolates can stain the bleached-rove treated with a sub-lethal concentration of a range of biocides or they can also reduce strength of the untreated-bleached-roves by degrading the residual non-cellulosic polysaccharides present on the fibre. However, the bacterial isolates did not cause staining on non-biocidetreated roves. The seven main bacteria isolated were Bacillus cereus mycoides, B. subtilis, Enterobacter cloacae, Klebsiella oxytoca, Micrococcus sp., Pseudomonas fluorescens and P. putida and all the isolates produced pectate-lyase on both sterilized-bleached fibre and in liquid culture. B. subtilis also produced xylanase on both substrates tested. None of the isolates produced cellulase on either substrate. Infra-red analysis of the stain produced by the bacteria suggested that compounds present were similar to melanin. Of the seven biocides tested (Dodigen {226X}, Durocid VA, AAS, SOPP, Preventol WB, Resista 4102, Rustol HEK and Sandocide), Dodigen (226X), Preventol WB, Resista 4102 and Rustol HEK offered the best protection of roves against bacterial staining.     

Development of a novel roving-treatment process employing sequential chelating agent and enzymatic stages, utilising thermal analysis for assessment of fibre and yarn quality

Despite the potential benefits of utilising enzyme-based treatments to remove specific non-cellulosic polysaccharide components from flax fibre prior to spinning, attempts to date have not proved successful. At present, techniques employing conventional chemical reagents are solely employed within this industry. To establish the feasibility of incorporating an enzyme treatment stage within a novel process sequence, small-scale laboratory test protocols have been developed and employed to screen the performance of a range of commercial enzyme formulations on commercial dew-retted flax rovings. Thermal analysis and physical testing permitted rapid assessment and the best-performing treatment sequences, based on Pectinex AR and Pentopan 500 BG, respectively (Novozymes A/S, Bagsvaerd, Denmark) were then successfully scaled-up for industrial spinning trials. The results of these trials have shown that treatment with a chelating agent followed by pectinase and peroxide bleaching processes is capable of producing good quality yarn. The compositional and structural changes occurring in the fibre at each stage of treatment were detected using derivative thermogravimetry, and revealed quantitative changes in weight loss, decomposition temperature and peak widths in response to process steps. Assessment of chemical and physical performance data for the yarns obtained indicates that such a process may have commercial applications, supplementing the repertoire of traditional techniques and reagents available to the industry.     

Effect of proteolytic enzyme on dyeing of wool with madder

In recent years, the use of low-environmental impact biotechnology giving rises to new types of treatment in the textile industry. The use of protease enzymes to improve some physical and mechanical properties such as smoothness, drapeability, dyeing affinity and water absorbency is particularly interesting. In this research, wool yarns were first treated with different concentrations of protease enzymes in water solution including 1, 2, 4 and 6% o.w.f. for 60 min. The dyeing process was then carried out on the treated yarns with madder (50% o.w.f.). Tensile strength of treated yarns was decreased due to enzyme treatment and it continued to decrease with an increase in enzyme concentration in solution. The L^* values decreased for the samples treated with enzyme. The wash and light fastness properties of samples were measured according to ISO 105-CO5 and Daylight ISO 105-BO1. The washing fastness properties of treated samples were not changed. In the case of light fastness properties, it was increased a little for 4% and 6% enzyme treated samples.     

Non-Cellulosic Polysaccharides from Cotton Fibre Are Differently Impacted by Textile Processing

Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non-cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being removed during bleaching and scouring. However, some forms of pectin are more resistant than others. Xylan and xyloglucan are affected in later processing steps and to a lesser extent, whereas callose showed a strong resistance to the chemical processing steps. This study shows that non-cellulosic polysaccharides are differently impacted by the treatments used in cotton textile processing with some hemicelluloses and callose being resistant to these harsh treatments.     

Characterization of cellulolytic enzyme system of Schizophyllum commune mutant and evaluation of its efficiency on biomass hydrolysis

Schizophyllum commune is a basidiomycete equipped with an efficient cellulolytic enzyme system capable of growth on decaying woods. In this study, production of lignocellulose-degrading enzymes from S. commune mutant G-135 (SC-Cel) on various cellulosic substrates was examined. The highest cellulase activities including CMCase, FPase, and β-glucosidase were obtained on Avicel-PH101 while a wider range of enzymes attacking non-cellulosic polysaccharides and lignin were found when grown on alkaline-pretreated biomass. Proteomic analysis of SC-Cel also revealed a complex enzyme system comprising seven glycosyl hydrolase families with an accessory carbohydrate esterase, polysaccharide lyase, and auxiliary redox enzymes. SC-Cel obtained on Avicel-PH101 effectively hydrolyzed all agricultural residues with the maximum glucan conversion of 98.0% using corn cobs with an enzyme dosage of 5 FPU/g-biomass. The work showed potential of SC-Cel on hydrolysis of various herbaceous biomass with enhanced efficiency by addition external β-xylosidase.     

Preliminary research on bamboo degumming with xylanase

The extraction of fibres from bamboo culm during the degumming process was performed with commercial xylanase. It is found that a combination of mild chemical pretreatment and enzymatic treatment is essential to achieve a high level of degumming, and better fibre separation. FTIR analysis of substances removed by enzyme treatment indicated that xylanase played an active role in the removal of non-cellulosic substances. Scanning electron microscopy revealed a relatively complete removal of gummy material from the surface of treated bamboo slices. On the basis of this investigation, it is suggested that the combination of mild chemical and enzymatic treatment is a promising method for bamboo degumming.     

Application of calcium alginate immobilized and crude pectin lyase from Bacillus cereus in degumming of plant fibres

Abstract

In this study, the purified pectin lyase was immobilized in calcium alginate beads and compared with crude enzyme for application in degumming of buel and banana plant fibres. From the data of scanning electron microscopy (SEM), it was observed that untreated buel fibres were covered by non-cellulosic materials (pectin, hemicelluloses and waxes) and the surface of enzymatically treated buel fibres looked smoother. Also, the crude alkaline pectin lyase treated buel fibre exhibited a considerably cleaner surface, which suggested that the crude pectin lyase could provide better degumming effects in comparison to the immobilized pectin lyase. In case of banana fibre, the FTIR spectroscopy showed that both crude and immobilized alkaline pectin lyase treatments of banana plant fibres were equally efficient in degumming. The enzymatic degumming of buel and banana with crude pectin lyase resulted in maximum release of galacturonide after 24?h for buel and 15?h for banana fibre. The optimum temperature for degumming of buel and banana fibres with crude pectin lyase was found to be 50?°C and 45?°C, respectively. Also, the maximum galacturonide was released with 200 and 250?U of pectin lyase for buel and banana fibre, respectively.     

Equine pre-caecal and total tract digestibility of individual carbohydrate fractions and their effect on caecal pH response

The working hypothesis was that a minor postprandial caecal pH decline would affect apparent total tract digestibility (ATTD) of the fibre fraction in horses and, hence, that soluble fibre would amplify fermentation and consequently increase ATTD of fibre. This study was a 4 × 4 Latin Square design with a sequence of 17 days adaptation to the ration followed by 8 sampling days. The feed rations consisted of only timothy hay (Group H), hay plus molassed sugar beet pulp combined with either whole oats (Group OB) or barley (Group BB) and hay plus loose chaff based concentrate (Group M). Four horses fitted with permanent caecal cannulas and collection harnesses were used. A pH electrode with logger was inserted through the cannula and caecal pH was recorded at 1 min intervals for 8 h. The mobile nylon bag technique was used to quantify pre-caecal loss (PCL) of individual feedstuffs. Fibre was analysed as dietary fibre (DF), non-starch polysaccharides, soluble non-cellulosic polysaccharides (S-NCP), insoluble non-cellulosic polysaccharide (I-NCP) and neutral detergent fibre. The ATTD of the S-NCP fraction was above 0.8, which was 60% higher than for the I-NCP fraction. The PCL of starch were 0.98 (oats) and 0.75 (barley). The BB diet lowered (p < 0.001) postprandial caecal pH more than the other diets and a significant correlation was found between the lowest pH and ATTD of I-NCP (r = ?0.66; p = 0.005). In conclusion, this study successfully measured the in vivo digestibility of individual fibre fractions and found that S-NCP was more digestible than the I-NCP, and that a single meal of unprocessed barley was sufficient to decrease caecal pH to such an extent that the fibre digestibility of the whole diet was negatively affected.     

Effect of the cellulose-binding domain on the catalytic activity of a β-glucosidase from <Emphasis Type="Italic">Saccharomycopsis fibuligera</Emphasis>

Enzyme engineering was performed to link the β-glucosidase enzyme (BGL1) from Saccharomycopsis fibuligera to the cellulose-binding domain (CBD2) of Trichoderma reesei cellobiohydrolase (CBHII) to investigate the effect of a fungal CBD on the enzymatic characteristics of this non-cellulolytic yeast enzyme. Recombinant enzymes were constructed with single and double copies of CBD2 fused at the N-terminus of BGL1 to mimic the two-domain organization displayed by cellulolytic enzymes in nature. The engineered S. fibuligera β-glucosidases were expressed in Saccharomyces cerevisiae under the control of phosphoglycerate-kinase-1 promoter (PGK1 _P ) and terminator (PGK1 _T ) and yeast mating pheromone α-factor secretion signal (MFα1 _S ). The secreted enzymes were purified and characterized using a range of cellulosic and non-cellulosic substrates to illustrate the effect of the CBD on their enzymatic activity. The results indicated that the recombinant enzymes of BGL1 displayed a 2–4-fold increase in their hydrolytic activity toward cellulosic substrates like avicel, amorphous cellulose, bacterial microcrystalline cellulose, and carboxy methyl cellulose in comparison with the native enzyme. The organization of the CBD in these recombinant enzymes also resulted in enhanced substrate affinity, molecular flexibility and synergistic activity, thereby improving the ability of the enzymes to act on and hydrolyze cellulosic substrates, as characterized by adsorption, kinetics, thermal stability, and scanning electron microscopic analyses.     

Optimization of enzyme complexes for lignocellulose hydrolysis

The ability of a commercial Trichoderma reesei cellulase preparation (Celluclast 1.5L), to hydrolyze the cellulose and xylan components of pretreated corn stover (PCS) was significantly improved by supplementation with three types of crude commercial enzyme preparations nominally enriched in xylanase, pectinase, and beta-glucosidase activity. Although the well-documented relief of product inhibition by beta-glucosidase contributed to the observed improvement in cellulase performance, significant benefits could also be attributed to enzymes components that hydrolyze non-cellulosic polysaccharides. It is suggested that so-called "accessory" enzymes such as xylanase and pectinase stimulate cellulose hydrolysis by removing non-cellulosic polysaccharides that coat cellulose fibers. A high-throughput microassay, in combination with response surface methodology, enabled production of an optimally supplemented enzyme mixture. This mixture allowed for a approximately twofold reduction in the total protein required to reach glucan to glucose and xylan to xylose hydrolysis targets (99% and 88% conversion, respectively), thereby validating this approach towards enzyme improvement and process cost reduction for lignocellulose hydrolysis.     

Increase of the Hydrophilicity of Polyethylene Terephthalate Fibres by Hydrolases from Thermomonospora fusca and Fusarium solani f. sp. pisi

Treatment of polyethylene terephthalate fibres with hydrolase preparations from Thermomonospora (Thermobifida) fusca and Fusarium solani f. sp. pisi resulted in an increase of the hydrophilicity of the fibres determined by measurement of their dyeing behaviour with reactive dyes and their water absorption ability. Reflectance spectrometry of treated fibres dyed with a reactive dye showed that the colour became more intense corresponding to an increase of hydroxyl groups on the fibre surfaces and indicated a stepwise peeling of the fibres by the enzymes comparable to the effects obtained by alkaline treatments. The synthetic fibres treated with the hydrolase from T. fusca also showed enhanced water absorption ability further confirming the increased surface hydrophilicity caused by the enzyme.     

Changes in the composition of cotton fibre cell walls during development

Purified cell walls, prepared from cotton fibres (Gossypium arboreum L.) at different growth stages, were subjected to successive extractions to give pectic, hemicellulosic, and -cellulosic fractions. The protein content and sugars obtained after hydrolysis of the total cell walls and of the various fractions were quantitatively estimated. The amount of protein in the fibre cell walls from one ovule reached a maximum value at the end of the elongation growth, decreased, and then reached a second maximum at the end of the secondary wall deposition. The absolute amounts of fucose, galactose, mannose, rhamnose, arabinose, uronic acid, and non-cellulosic glucose residues all reached a maximum at the end of the primary wall formation or at the beginning of the secondary wall formation. Only the absolute amounts of xylose and of the cellulosic glucose residues increased until the end of the fibre development. Most conspicuous was the decrease in the absolute amounts of non-cellulosic glucose and of arabinose residues during the secondary wall formation, possibly indicating a turnover of at least some of the hemicellulosic wall material.Abbreviations DPA days post anthesis - TLC thin layer chromatography - SDS sodium dodecyl sulphate     

Lipase immobilisation on to polymeric membranes

Lipase (EC 3.1.1.3) from Candida rugosa was covalently immobilised on to cellulose, cellulose derivatives (cellulose acetate and cellulose phthalate) and cellulose composite membranes using activating agents such as sodium periodate or carbodiimide. Other non-cellulosic polymeric membranes (nylon, polyurethane, chitosan and hydroxyethyl methacrylate-co-methyl methacrylate) were also prepared and used for lipase immobilisation. The results obtained showed that the expressed activities are of the same order of magnitude for similar enzyme loadings when compared with those obtained from literature.     

Hydrolysis and transformation of cellulose with Aspergillus niger IBT-90 enzymes

Hydrolysis and transformation of Fibrenier cellulose (USA) with enzymes from Aspergillus niger IBT-90 was studied. The process was performed at 50°C and pH 4.8 for 24 h using an enzyme complex either as a properly diluted culture filtrate or as a mixture of isolated and purified enzymes from A.niger IBT-90. In the latter experiments, enzyme-substrate ratios expressed as units of activity per 1 g of cellulose were as follows: endoglucanase E₁ and E₂, 40; β-glucosidase, 40 and cellobio-hydrolase, 2. Cellulose concentration was 5%. It was proved that the crude celluloytic complex from A. niger IBT-90 exhibits higher efficiency in the decomposition of cellulose in comparison to the mixture of enzymes isolated from this complex, as was revealed in assays of reducing sugars and determinations of light transmission throughout cellulose fibres using a computer analysis of the microscopic image. Comparison of both the endoglucanases E₁ and E₂ showed that the first enzyme is more active against cellulose. It liberated more reducing sugars and caused more significant decomposition of fibres. The predominant effect of the endoglucanase E₂ was a smoothing of the fibre surface. The cellobiohydrolase split a cellulose fibre into many short fibres.     

Biocatalytic modification of polyethylene terephthalate fibres by esterases from actinomycete isolates

The modification of polyethylene terephthalate (PET) fibres by extracellular enzymes produced by actinomycetes was investigated. Cultivation of isolates in media containing PET yarn and suberin, a plant polyester composed of aliphatic and aromatic moieties, induced the production of p-nitrophenyl butyrate hydrolyzing enzymes. Incubation of enzyme preparations from the isolates M5, M9 and Thermomonospora fusca KW3b with PET yarn resulted in an increase in the absorbance of the reaction mixtures at 240 nm indicating the release of terephthalic acid or its esters catalyzed by the enzymes. The results of dyeing of enzyme-treated PET fabrics with a reactive dye (CI Reactive Red 2) indicated an increase in hydroxyl groups at the fibre surfaces as a result of the enzyme treatment.     

Production of cellulolytic enzymes from fungi and use in the saccharification of palm cake and palm fibre

Aspergillus niger ATCC 6275 possesses the highest carboxymethyl-cellulase, xylanase and -glucosidase activities under liquid and solid cultivations compared withMyceliophthora thermophila IFO 31843 and an isolate, F11. Palm cake proved to be a better substrate for enzyme production and saccharification than palm fibre. Saccharification of these two substrates, using crude enzyme solutions from three fungi and commercial enzymes, was investigated.     

Degumming of silk fabric with several proteases

A crêpe silk fabric was treated with different alkaline (3374-L, GC 897-H), neutral (3273-C), and acid (EC 3.4 23.18) proteases with the aim to study their effectiveness as degumming agents. Proteases were used under optimum conditions of pH and temperature, while enzyme dosage (0.05-2 U/g fabric) and treatment time (5-240 min) were changed in order to study the kinetics of sericin removal. Degumming loss with soap and alkali was 27 wt.%. The maximum amount of sericin removed in 1 h was 17.6, 24, and 19 wt.% for 3374-L (2 U/g fabric), GC 897-H (1U/g fabric), and 3273-C (0.1 U/g fabric), respectively. Under the experimental conditions adopted, EC 3.4 23.18 was almost ineffective as a degumming agent. Degumming loss increased as a function of the treatment time, reaching a value of 25 wt.% with 1 U/g fabric of 3374-L. The morphological analysis showed that sericin was completely removed from the warp yarns of the crêpe fabric, while the highly twisted weft yarns still exhibited the presence of sericin deposits within the most internal parts of the close fibre texture. The chromatographic pattern of soluble sericin peptides changed as a function of the kind of enzyme used, enzyme dosage, and treatment time. A mixture of peptides from 5 to 20 kDa in weight, with a weight-average molecular weight of about 12 kDa was obtained.     

Ultrafiltration of raw sewage using an immobilized enzyme membrane

Ultrafiltration of raw sewage was performed using multiple enzymes immobilized on non-cellulosic, ultrafiltration membranes. An increase of 12% in the permeate flux rate at quasi-steady state was observed due to the action of the immobilized enzymes. Enzymes were immobilized by physical sorption to minimize the loss of ultrafiltration capability of the membrane, due to the immobilization process. A mathematical model based on diffusive transport and enzymatic action is presented. A standard Marquardt algorithm and a fourth-order Runge-Kutta integration routine were used for estimation of the non-linear parameters in the model. A comparison of data presented here with the data reported earlier on the ultrafiltration of NFDM (non-fat dry milk), showed that the enzyme-membrane has a longer half-life in the case of NFDM than for raw sewage. Furthermore, the first-order enzyme decay rate is much faster in the multiple enzyme system used in raw sewage filtration than in the single enzyme system used in the ultrafiltration of NFDM.     

Specificities of a chemically modified laccase from Trametes hirsuta on soluble and cellulose-bound substrates

Laccases could prevent fabrics and garments from re-deposition of dyes during washing and finishing processes by degrading the solubilized dye. However, laccase action must be restricted to solubilized dye molecules thereby avoiding decolorization of fabrics. Chemical modification of enzymes can provide a powerful tool to change the adsorption behaviour of enzymes on water insoluble polymers. Polyethylene glycol (PEG) was covalently attached onto a laccase from Trametes hirsuta. Different molecular weights of the synthetic polymer were tested in terms of adsorption behaviour and retained laccase activity. Covalent attachment of PEG onto the laccase resulted in enhanced enzyme stability while with increasing molecular weight of attached PEG the substrate affinity for the laccase conjugate decreased. The activity of the modified laccases on fibre bound dye was drastically reduced decreasing the adsorption of the enzyme on various fabrics. Compared to the 5 kDa PEG laccase conjugate (K/S value 47.60) the K/S value decreased much more (47.96–46.35) after the treatment of dyed cotton fabrics with native laccase.     

Effects of fibre-degrading enzymes in combination with different fibre sources on ileal and total tract nutrient digestibility and fermentation products in pigs

ABSTRACT

The study was conducted to determine effects of a complex of fibre-degrading enzymes (xylanase, cellulase and β-glucanase) on nutrient digestibility, fibre fermentation and concentrations of short chain fatty acids (SCFA) at different parts of digestive tract in pigs fed different fibre-rich ingredients. A total of 36 barrows fitted with T-cannulas in the distal ileum (initial body weight of 41.1 ± 2.7 kg) were randomly allotted to six dietary treatments with three different high-fibre diets including maize bran (MB), sugar beet pulp (SBP) and soybean hulls (SH) with or without supplementation of fibre-degrading enzymes. Enzyme supplementation improved (p < 0.05) apparent ileal digestibility (AID) of dietary gross energy (GE), crude protein, dry matter (DM), organic matter (OM), total dietary fibre (TDF), neutral detergent fibre (NDF) and apparent total tract digestibility (ATTD) of dietary GE, DM, OM, TDF, insoluble dietary fibre (IDF) when pigs were fed MB, SBP or SH diets. When compared to the SBP and SH diets, the AID of GE, DM, ash, OM and NDF in diet MB was higher (p < 0.05), but the hindgut disappearance and ATTD of nutrients, except for ether extract and crude ash, were lower (p < 0.05). Enzyme supplementation increased acetate and total SCFA concentrations in ileal digesta and faeces of pigs. In conclusion, enzyme addition improved IDF fermentation and SCFA concentration in the whole intestine of pigs, and there was a large variation of digestibility of fibre components among MB, SH and SBP owing to their different fibre composition. Therefore, fibre-degrading enzymes should be applied to fibrous diets to improve efficient production of swine, especially considering low fibre digestibility of fibre-rich ingredients.